In the field of air pollution control, one often needs to sample the quality of a moving

Chapter 9, Problem 9-52

(choose chapter or problem)

In the field of air pollution control, one often needs to sample the quality of a moving airstream. In such measurements a sampling probe is aligned with the flow as sketched in Fig. P952. A suction pump draws air through the probe at volume flow rate V # as sketched. For accurate sampling, the air speed through the probe should be the same as that of the airstream (isokinetic sampling). However, if the applied suction is too large, as sketched in Fig. P952, the air speed through the probe is greater than that of the airstream (super iso kinetic sampling). For simplicity consider a two-dimensional case in which the sampling probe height is h 5 4.58 mm and its width (into the page of Fig. P952) is W 5 39.5 mm. The values of the stream function corresponding to the lower and upper dividing streamlines are cl 5 0.093 m2/s and cu 5 0.150 m2/s, respectively. Calculate the volume flow rate through the probe (in units of m3/s) and the average speed of the air sucked through the probe.